A tiny patch can take images of muscles and cells underneath your skin

Researchers built a device that can act like a tiny ultrasound.
Close-up of patient's neck with a wearable ultrasound patch
This small patch can monitor tissue up to four centimeters below the skin. UC San Diego Jacobs School of Engineering

Researchers at the University of California San Diego have invented an adhesive, elastic patch capable of performing ultrasounds—but don’t expect any baby pictures just yet. Even without the social media fodder, the new wearable technology could soon provide an extremely useful tool for a wide array of medical monitoring procedures.

As detailed in a paper published on Monday in Nature Biomedical Engineering, a team led by nanoengineering professor Sheng Xu has developed a tiny, wearable device capable of measuring tissue stiffness up to 4 centimeters underneath the skin with a spatial resolution of 0.5 millimeters. In a statement, study coauthor and postdoctoral researcher Hongjie Hu explained that the group “integrated an array of ultrasound elements into a soft elastomer matrix and used wavy serpentine stretchable electrodes to connect these elements,” thus creating a conformable patch for portable medical monitoring.

According to the team’s paper, the device is composed of a 16-by-16 array of transducer elements connected via a seven-layer electrode. This is all protected by a waterproof and biocompatible silicone elastomer. A backing layer made from a composite of silver-epoxy helps absorb excessive vibrations to broaden bandwidth capabilities and improve resolution.

[Related: Wearable liquid pumps could one day regulate body temperature.]

All together, the patch comfortably conforms and “acoustically couples” to a patient’s skin to take repeated, three-dimensional images of underlying tissue. Compared with traditional ultrasound technology, the new patch can take the monitoring outside of hospital settings and eliminates the need for staff assistance. “This allows patients to continuously monitor their health status anytime, anywhere,” added Hu.

One significant challenge the team initially encountered involved the actual manufacturing of the patch. Traditional fabrication methods often require high-temperature bonding procedures that thermally damage the device’s sensitivity. To solve this problem, Xu’s team replaced their patch’s soldering paste with a conductive epoxy that bonded at room temperature, thus avoiding any burn-related problems.

Already, the team’s patch shows promise across a number of medical areas and research. Among the potential usages: monitoring the progression of cancerous cells, which often stiffen as they spread; assessing sports injuries affecting tendons, ligaments, and muscles; and analyzing the efficacy of treatments for liver and cardiovascular diseases alongside chemotherapy results. According to UC San Diego’s announcement, the ability to continuously monitor these health issues could aid in avoiding misdiagnosis and fatalities while also reducing costs via the new, non-invasive alternative to traditional hospital procedures.